Hello everyone
First of all, thank you for your help.
Our new build now finally has a hip roof....
The joist layer of the interior ceiling rests on the ring beam. On top of the joists is the wall plate. This creates a gap between the ring beam and the roof from the outside that needs to be insulated...
I have now closed this gap with OSB boards. I plan to attach the insulation to these by gluing or screwing.
Now my question...
When installing the insulation boards between the exterior rafters, should they be fixed flush against the rafters, or should there be an air gap that is then filled with foam?
My concern is that the wood may move, pushing the insulation boards out and causing cracks in the external render.
Thank you for your suggestions, and I hope I was able to clearly explain what I mean.
First of all, thank you for your help.
Our new build now finally has a hip roof....
The joist layer of the interior ceiling rests on the ring beam. On top of the joists is the wall plate. This creates a gap between the ring beam and the roof from the outside that needs to be insulated...
I have now closed this gap with OSB boards. I plan to attach the insulation to these by gluing or screwing.
Now my question...
When installing the insulation boards between the exterior rafters, should they be fixed flush against the rafters, or should there be an air gap that is then filled with foam?
My concern is that the wood may move, pushing the insulation boards out and causing cracks in the external render.
Thank you for your suggestions, and I hope I was able to clearly explain what I mean.
The insulation boards are glued in place.
Without exterior insulation, they are installed in the cavities between the rafters.
When exterior insulation is applied, the crosswise installation of the insulation boards stops about 1.5 meters (5 feet) below the roof. Then the insulation boards are glued vertically up to the underlay membrane, and only after that the remaining gaps are insulated.
The angle of the roof pitch is transferred to the short side of the insulation board, cut with a polystyrene cutter (hot wire cutting tool), pressed upwards, and the position of the rafters is marked.
Then the space for the rafters is cut out from the insulation board.
It is pressed up and glued to the wall, flush with the lower boards.
Since a perfect cut is not possible, the gaps inside and outside are filled with expanding foam, but the foam must not be applied directly to the underlay membrane.
Expanding foam (just like white polystyrene) is not UV resistant and should not be left exposed to the weather for long periods without protection.
Without exterior insulation, they are installed in the cavities between the rafters.
When exterior insulation is applied, the crosswise installation of the insulation boards stops about 1.5 meters (5 feet) below the roof. Then the insulation boards are glued vertically up to the underlay membrane, and only after that the remaining gaps are insulated.
The angle of the roof pitch is transferred to the short side of the insulation board, cut with a polystyrene cutter (hot wire cutting tool), pressed upwards, and the position of the rafters is marked.
Then the space for the rafters is cut out from the insulation board.
It is pressed up and glued to the wall, flush with the lower boards.
Since a perfect cut is not possible, the gaps inside and outside are filled with expanding foam, but the foam must not be applied directly to the underlay membrane.
Expanding foam (just like white polystyrene) is not UV resistant and should not be left exposed to the weather for long periods without protection.
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